JPH0412267Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an air suspension used in motorcycles and the like.

(Prior Art) As an air suspension used for a front fork of a motorcycle, for example, one shown in FIG. 5 is known. This air suspension has a seat pipe 52 installed in a bottom case 51, and the bottom case 51 and the seat pipe 5
A fork pipe 53 is slidably fitted from the upper part between the fork pipe 53 and the gas chamber 54.
The lower side serves as an oil chamber 55 in which hydraulic oil is sealed.

A piston portion 56 is formed at the tip of the seat pipe 52 to slide on the inner circumferential surface of the fork pipe 53, and a valve 57 is installed inside the lower end of the fork pipe 53. Furthermore, a bottom case 51 is provided on the outer peripheral surface of the lower end of the fork pipe 53.
A bush 58 that slides on the inner circumferential surface is fitted, and a fork pipe 53 is fitted on the upper inner circumferential surface of the bottom case 51.
A bush 59 is fitted to slide on the outer circumferential surface, and an oil seal 60 for sealing hydraulic oil is fitted to the inner circumferential surface of the upper end of the bottom case 51.

(Problem to be solved by the invention) As mentioned above, in the air suspension in which the gas and hydraulic oil are not completely separated, the gas in the upper gas chamber 54 mixes into the hydraulic oil due to the operation of the air suspension. An emulsion is generated, and the gas mixed in the hydraulic oil flows from chamber A to chamber B through between the outer peripheral surface of the piston part 56 of the seat pipe 52 and the inner peripheral surface of the fork pipe 54 or through the upper hole of the sheet pipe.
It enters the chamber C through the valve 57, or it directly enters the chamber C from the chamber A through the lower hole of the seat pipe, and then from the chamber C between the outer circumferential surface of the bush 58 of the fork pipe 53 and the inner circumferential surface of the bottom case 51. Gas enters chamber D through the fork pipe hole, and gas accumulates in chamber D from chamber D or chamber B through the fork pipe hole. Even if the gas accumulated in chamber D is fully extended, it cannot be returned to chambers B and A through the fork pipe holes and remains.

Therefore. When the fork pipe 54 moves up and down, the gas in the chamber D tries to escape through the space between the inner circumferential surface of the bush 59 of the bottom case 51, the inner circumferential surface of the oil seal 60 of the fork pipe 53, and the outer circumferential surface of the fork pipe 53. So, bottom case 51
The oil seal 60 has to seal not only hydraulic oil but also gas, which reduces reliability against gas leaks.

(Means for solving the problem) In order to solve the above problem, the present invention installs a cylinder between the bottom case and the seat pipe,
An orifice was formed in the upper part of this cylinder to communicate the inner and outer gaps, and an orifice was further formed to communicate the lower part of the gap between the bottom case and the cylinder into the seat pipe.

(Function) Hydraulic oil mixed with gas from the lower part of the bottom case enters the gap between the fork pipe and the cylinder, but when the fork pipe moves upward during the extension process, this hydraulic oil flows from the upper orifice of the cylinder to the cylinder and bottom case. The gas mixed in the hydraulic oil also returns to the seat pipe and returns to the upper gas chamber through the orifice at the bottom of the cylinder.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a cross-sectional view of an air suspension according to the present invention, and FIG. 2 is an enlarged cross-sectional view of essential parts of the air suspension.

A seat pipe 2 is installed at the bottom of the bottom case 1 of the air suspension, and a fork pipe 3 is inserted from above between the bottom case 1 and the seat pipe 2.
A gas cap 4 is fixed to the upper part of the fork pipe 3 so that the upper part serves as a gas chamber 5 for sealing gas, and the lower part serves as an oil chamber 6 for sealing hydraulic oil. Alternatively, it is also possible to enlarge the fork pipe at the top as shown in Figure 4.

Further, a valve 8 that slides into contact with the outer peripheral surface of the seat pipe 2 is fitted on the inner peripheral surface of the lower end of the fork pipe 3, and an orifice 9 that communicates between the inside and outside is formed above the valve 8. A piston portion 10 is formed at the upper end portion to be in sliding contact with the inner circumferential surface of the fork pipe 3, and orifices 11 and 12 are formed below the piston 10 to communicate between the inside and outside.

Furthermore, a cylinder 15 is installed inside the bottom case 1 with a gap between the bottom case 1 and the fork pipe 3, and the outer peripheral surface of the lower end of the fork pipe 3 is in sliding contact with the inner peripheral surface of the cylinder 15. A tube guide 17 whose lower surface abuts the upper end of the cylinder 15 is fitted on the inner peripheral surface of the upper end of the bottom case 1.
A bush 18 that slides on the outer circumferential surface of the fork pipe 3 is fitted on the inner circumferential surface, and an oil seal 19 that slides on the outer circumferential surface of the fork pipe 3 is fitted above the bush 18.

An orifice 21 is formed in the upper part of the cylinder 15 to communicate between the inside and outside, that is, the gap between the outer circumferential surface of the fork pipe 3 and the gap between the inner circumferential surface of the bottom case 1. Furthermore, a hollow center bolt 23 facing into the seat pipe 2 is attached to the cap 22 forming the bottom of the bottom case 1, and the cap 22 of the bottom case 1 and the center bolt 2
3 is an orifice 2 that communicates the lower part of the gap between the cylinder 15 and the bottom case 1 into the seat pipe 2.
4, 25 and an air guide 23 at the upper end.
A is provided to prevent air from returning from the orifice 12 of the seat pipe.

The operation of the air suspension constructed in this way will be explained.

First, when the fork pipe 3 moves downward in the bottom case 1 during the compression stroke, the check valve of the valve 8 at the lower end of the fork pipe 3 opens, so the hydraulic oil in the chamber E flows into the chamber F through the valve 8. and enters the seat pipe 2 from the orifice 11 of the seat pipe 2, and enters the seat pipe 2 from the orifice 12 of the seat pipe 2,
Return to room G.

Also, when the fork pipe 3 moves upward in the bottom case 1 during the extension process, the pressure in the chamber F increases and the hydraulic oil in the chamber F flows out from the orifice 11 of the seat pipe 2 into the seat pipe 2. , flows out from the valve 8 into the chamber E, and further flows out from the orifice 9 of the fork pipe 3 into the chamber H, which is the gap between the fork pipe 3 and the cylinder 15.

The hydraulic oil that has flowed into the chamber H flows into the chamber I, which is the gap between the cylinder 15 and the bottom case 1, through the orifice 21 of the cylinder 15 as the fork pipe 3 moves upward, and then flows into the chamber I, which is the gap between the cylinder 15 and the bottom case 1. It enters the center bolt 23 from inside the cap 22 and through the orifices 24 and 25 of the center bolt 23, and returns to the upper chamber G from inside the seat pipe 2 while being guided by the air guide 23a. Therefore, the gas mixed in the hydraulic oil also returns to the gas chamber 5, and there is no gas accumulation in the lower part of the oil seal 19, so that the oil seal 19 only needs to seal the oil.

At this time, the air guide 23a guides the hydraulic oil so that the hydraulic oil that has leaked into the seat pipe 2 does not return from the orifice 12 of the sheet pipe 2 into the chamber F, thereby preventing the hydraulic oil from being mixed into the hydraulic oil. The gas reliably returns to the upper gas chamber 5.

As shown in FIG. 3, if the upper end of the cylinder 15 is fitted into the inner peripheral surface of the tube guide 17 and held between the tube guide 17 and the bush 18, the cylinder 15, the bottom case 1 and the fork can be connected. The gap with the pipe 3 can be maintained more stably.

(Effect of the invention) As explained above, according to the invention, a cylinder is provided between the bottom case and the seat pipe, and the hydraulic oil between the cylinder and the fork pipe is supplied from between the bottom case and the cylinder to the bottom case. Since the gas mixed in the hydraulic oil also returns to the upper gas chamber from within the seat pipe, the reliability of gas leakage is improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the air suspension according to the present invention, Fig. 2 is an enlarged sectional view of the main part of the air suspension, and Fig. 3 is a sectional view of the main part showing another example of the cylinder support part of the air suspension. , FIG. 4 is a diagram showing another embodiment, and FIG. 5 is a sectional view of a conventional air suspension. In addition, in the drawing, 1 is a bottom case, 2 is a seat pipe, 3 is a fork pipe, 5 is a gas chamber, 6 is an oil chamber, 8 is a valve, 15 is a cylinder, 21, 24,
25 is orifice, 17 is tube guide, 22
is the cap, and 23 is the center bolt.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A seat pipe is installed in the bottom case, and a fork pipe is slidably fitted between the bottom case and the seat pipe, and the interior contains hydraulic oil and In an air suspension filled with gas, a cylinder is installed inside the bottom case with a gap between the bottom case and the seat pipe, and an orifice is installed in the upper part of the cylinder to communicate the gap between the inside and outside. form,
The air suspension is further characterized in that an orifice is formed in the lower part of the bottom case to communicate the lower part of the gap between the bottom case and the cylinder with the inside of the seat pipe. (2) The air suspension according to claim 1 of the utility model registration, wherein an air guide is attached to the lower part of the seat pipe to guide the gas flowing out from the orifice upwards of the seat pipe.